In a conventional semiconductor device, a semiconductor chip, input and output matching circuits are placed on a base substrate. That is, the semiconductor chip and the input and output matching circuits are placed in a metal frame body formed on the base substrate. In addition, a lid is placed on the frame body to seal the inside of the frame body.
In such a semiconductor device, the semiconductor chip is connected to the input and output matching circuits formed on input and output sides, respectively, through a plurality of wires.
Each of the input and output matching circuits is connected to an input or output line connected with either of an input lead or an output lead through a connection portion composed of a plurality of wires.
Each of the input and output lines connected to the input and output matching circuits, respectively, is formed in a manner that one end thereof connected with the input or output lead has the same width as that of the other end thereof connected with the plurality of wires, as disclosed in Japanese Patent Application Laid-Open Nos. 2003-115732 and 2007-81125.
In the conventional semiconductor device, when a large amount of power is output, the output power may exceed an allowable electric power at the connection portion connecting the input or output line and the input or output matching circuit. In this case, there is posed a problem that wires composing the connection portion may melt.
This melting of wires is resolved by increasing the number of wires composing the connection portion. This is because increasing the number of wires can increase the allowable electric power at the connection portion.
However, in the conventional semiconductor device, the number of wires composing the connection portion is limited by a width of a line. Accordingly, the conventional semiconductor device has various electrical problems.
A first problem is that the electric power which the semiconductor device can output is limited because limitation in the number of wires restricts the maximum allowable electric power at the connection portion.
A second problem is that impedance matching between the connection portion and the input and output matching circuits is difficult because limitation in the number of wires restricts the minimum impedance of the connection portion. Accordingly, the conventional semiconductor device has a problem that flexibility in a circuit design of the input and output matching circuits is limited due to an impedance of the connection portion.